Solid-state self-emission display and its production method

ABSTRACT

The present invention provides a solid state light-emissive display apparatus of high brightness and efficiency, high reliability, and of thin type, and method of manufacturing the same at low cost. 
     Said apparatus has the luminous thin film made up by laminating or mixing crystal fine particle coated with insulator ( 5 ) of nm size and fluorescent fine particles ( 7 ) of nm size, and the lower electrode and the transparent upper electrode sandwiching said luminous thin film, wherein the electrons injected from said lower electrode are accelerated in the crystal fine particle coated with insulator layer ( 6 ) not being scattered by phonons to become high energy ballistic electrons, and form excitons ( 13 ) by colliding excitation of fluorescent fine particles. Since said fluorescent fine particles are of nm size, the exciton concentration is high, and luminescence intensity by extinction of excitons is also high.

TECHNICAL FIELD

The present invention relates to solid state light-emissive displayapparatus utilizing a quantum size effect and method of manufacturingthe same.

BACKGROUND ART

The display apparatuses using liquid crystals are lately in wide spreaduse, but these are not the best in such properties as energy-saving orbrightness, since a liquid crystal display apparatus uses backlight inprinciple. For this reason, the research and development are widelyproceeding for a solid state light-emissive display apparatus, aiming torealize high brightness, energy-saving, flat type, and high reliabilityrather more than liquid crystal.

As an existing solid state light-emissive display apparatus, there isEL(Electro Luminescence) display apparatus. EL display apparatus iscomposed of pixels each of which has a semiconductor layer includinglight emission center atoms and insulator layers sandwiching saidsemiconductor layer. As a light emission center atom, such elements thatemit visible fluorescence, for example, Mn or rare earth elements areused, and as a semiconductor layer, such semiconductors that have largerband gap energy than visible light, for example, ZnS or else are used,and as insulator layers, such insulators that have a property whichprevents dielectric breakdown of said semiconductor layers, for example,thin films of SiO₂ or Si₃N₄ are used.

EL display apparatus emits light as following, electrons in asemiconductor are accelerated by high electric field imposed throughinsulation layers, the accelerated electrons collide to light emissioncenter atoms to be excited, and the excited light emission center atomsemit fluorescence light. Therefore it is the specific feature of ELdisplay apparatus that electric energy directly converts to lightenergy.

However, there are problems such that light emission efficiency is lowand dielectric breakdown tends to occur, because considerably highelectric field (10⁶ V/cm or higher) is necessary to accelerate theelectrons to such a high energy state (hot electron state) to emit ELlight against the energy dispersion by phonon scattering. There are alsosuch EL display apparatuses using organic materials as the semiconductorlayer, but they also have problems such that emission efficiency easilybecomes lower as organic materials are unstable and readily deteriorate.

There are also FED (Field Emission Device) display apparatuses as thedisplay apparatuses to generate fluorescence by colliding and excitinglight emission center atoms by accelerated electron (ballisticelectron). However, an FED display apparatus has its problems such that,though it can emit light at relatively low electric field, it requiresvacuum space and hence it can not be made to a flat and all-solid statetype, since it emits out electrons into vacuum by using a field-emissiontype electron gun and accelerates them in vacuum.

DISCLOSURE OF THE INVENTION

Taking into consideration the afore-mentioned problems, the object ofthe present invention is to provide a solid state light-emissive displayapparatus which has much superior properties to existing displayapparatuses in brightness, efficiency, reliability, and a thin type. Andalso the other object of the present invention is to provide a method ofmanufacturing the said apparatus, which manufactures it at low cost.

In order to achieve the object mentioned above, there is provided asolid state light-emissive display apparatus according to the presentinvention, characterized in that it has light emitting pixels comprisingof a luminous thin film composed of crystal fine particles ofnm(nanometer) size coated with insulator and fluorescent fine particlesof nm size in a form of laminating of two said each particle layers orin a form of mixed layer of said two particles, and a lower electrodeand a transparent upper electrode sandwiching said luminous thin film,whereby to obtain luminous display by impressing alternating voltage ordirect current voltage between said upper and lower electrodes.

In the solid state light-emissive display apparatus according to thepresent invention, said crystal fine particle of nm size coated withinsulator is characterized in that it consists of a semiconductor or ametal single crystal fine particle of nm size and insulator film of nmthickness coating the surface of said single crystal fine particle.

In the solid state light-emissive display apparatus according to thepresent invention, said crystal fine particle of nm is preferably anintrinsic or impurity doped Si single crystal fine particle of nm size,and said insulator film is a SiO₂ film of nm thickness coating thesurface of said Si single crystal fine particle.

Also preferably, said fluorescent fine particle of nm size is asemiconductor fine particle having a band gap energy corresponding to anenergy ranging from ultraviolet light to visible light. Said fluorescentfine particle of nm size may have a donor or/and an acceptor. Also saidfluorescent fine particle of nm size may be a semiconductor fineparticle involving luminous atoms or luminous atom ions.

According to the above mentioned makeup, the voltage impressed betweenthe lower and the upper electrodes is distributed to the insulator filmscoating the crystal fine particles of nm size in the luminous thin film,the electrons injected from the lower electrode are accelerated by theelectric field distributed to the insulator film, pass through saidinsulator film by tunneling or resonant tunneling, and pass through thesingle crystal fine particle of nm size without being scattered byphonons (Refer to JP 2001-332168, for example). The electrons repeat theabove mentioned process for each adjacent crystal fine particle of nmsize coated with insulator as a result to obtain high kinetic energy,and collide with the fluorescent fine particles of nm size. If thekinetic energy of the colliding electron is higher than the band gapenergy of the fluorescent fine particle, a free electron and a hole aregenerated in the fluorescent fine particle, and a free exciton isgenerated from these free electron and hole.

Since the fluorescent fine particle is of nm size, said electron andhole are enclosed in space of nm size, the concentration of said freeexciton is raised, and hence the luminous intensity by extinction ofsaid free excitons is increased.

Also, in case that the fluorescent fine particle has a donor or/and anacceptor, the generated electron and hole form a bound exciton via adonor or/and an acceptor. Since the fluorescent fine particle is of nmsize, the electron and the hole are enclosed in space of nm size, hencethe concentration of bound exciton is raised, and the luminous intensityby extinction of said bound excitons is increased.

Also, in the case of fluorescent fine particle including luminous atomsor luminous atom ions, since the electrons having high kinetic energyare generated in large quantity by crystal fine particles coated withinsulator, luminous atoms or luminous atom ions in fluorescent fineparticles are excited in large quantity, and luminous intensity isincreased.

Thus, according to the present invention, since electrons can beaccelerated without energy loss and exciton concentration can be high,the luminous efficiency and brightness are high. Also, since theluminous thin film is thin and can emit light by itself, the apparatusof this invention can be made extremely thin. Also, since the appliedvoltage is low, reliability is high.

And, the solid state light-emissive display apparatus according to thepresent invention is characterized in that the upper and the lowerelectrodes are configurated in a form of matrix configuration, and theintersected region of the upper and the lower electrode is used as alight emitting pixel by simple matrix driven with these electrodes.

According to the makeup mentioned above, an image display apparatus ofhigh efficiency, high brightness, thin type, and high reliability can beprovided.

Further, the solid state light-emissive display apparatus of the presentinvention is characterized in that wirings for scanning and wirings forsignals are provided in a form of matrix electrode configuration, a thinfilm transistor is provided at each intersection of said scanning andsignal wirings, the gate electrode of said thin film transistor isconnected to scanning wiring, the drain electrode of said thin filmtransistor is connected to signal wiring, the source electrode of saidthin film transistor is connected to an electrode of a light emittingpixel, a luminous thin film is sandwiched by said electrode and upperelectrode of said light emitting pixel, wherein each light emittingpixel can be actively driven by said each thin film transistor selectedby said scanning and signal wirings.

According to the makeup mentioned above, since the optical distinctionratio between adjacent pixels can be made high, an image displayapparatus of high efficiency, high brightness, thin type, and highreliability, and extremely high resolution can be provided.

Next, in order to achieve the other object mentioned above, there isprovided in accordance with the present invention a method ofmanufacturing the solid state light-emissive apparatus characterized inthat it comprises the steps of: forming Si single crystal fine particlesof nm size being floating in an atmosphere by pyrolyzing SiH₄ gas, andconveying said floating Si single crystal fine particles into O₂ gasatmosphere, whereby the surface of said Si single crystal fine particlesto be coated with SiO₂ film of nm thickness.

According to the makeup described above, since the Si single crystalfine particles are formed in a state of floating and SiO₂ film is formedon the surface of said floating Si single crystal fine particles in astate of floating, Si single crystal fine particles do not contactmutually not to be combined with each other, and hence mutually isolatedSi single crystal fine particles coated with SiO₂ film can be provided.

By using above mentioned particles, a solid state light-emissiveapparatus can be manufactured by dissolving the crystal fine particlesof nm size coated with insulator and the fluorescent fine particles ofnm size into respective solvents, soaking a substrate and then taking itout in turn with respective solvents, whereby to laminate the layers ofthe crystal fine particle of nm size coated with insulator and thelayers of fluorescent fine particle of nm size.

According to the makeup above mentioned, a mono-layer which consists ofthe crystal fine particles coated with insulator being denselyaggregated on the substrate, is obtained by one time processing ofsoaking a substrate into the solvent dissolving the crystal fineparticles of nm size coated with insulator and taking out there-from,and the desired thickness of the layer is obtained by repeating theabove processing. Then, a mono-layer which consists of the fluorescentfine particles of nm size being densely aligned on the layer of thecrystal fine particles of nm size coated with insulator on thesubstrate, is obtained by one time processing of soaking the substrateinto the solvent dissolving fluorescent fine particles of nm size andtaking out there-from, and the desired thickness of the layer isobtained by repeating the above processing. As the result, the luminousthin film can be provided, in which the crystal fine particle layer ofthe desired film thickness and the fluorescent fine particle layer ofthe desired film thickness are laminated.

According to the above mentioned method, since those fine particles canbe densely packed with only a few gaps between those fine particles inthe luminous thin film, it can emit light at high efficiency. And, sinceno expensive apparatus is needed for the manufacturing, it costs arelow.

And the luminous thin film of the solid state light-emissive apparatusaccording to the present invention can be also manufactured bydissolving the crystal fine particles of nm size coated with insulatorand the fluorescent fine particles of nm size into common solvent, bysoaking a substrate into the solvent and then taking it out from thesolvent, whereby to make a mixed layer of the crystal fine particles ofnm size coated with insulator and the fluorescent fine particles of nmsize.

According to the above mentioned makeup, a mono layer which consists ofthe crystal fine particles coated with insulator and the fluorescentfine particles of nm size being densely and mutually aligned on thesubstrate, is obtained by one time processing of soaking a substrateinto the solvent and taking it out there-from, and the desired thicknessof the layer is obtained by repeating the above processing.

According to the above mentioned method, since those fine particles canbe densely packed with only a few gaps between those fine particles inthe luminous thin film, it can emit light at high efficiency. And, sinceno expensive apparatus is needed for the manufacturing, costs are low.The afore mentioned crystal fine particles of nm size coated withinsulator preferably consists of a single crystal fine particle of asemiconductor or a metal of nm size coated with insulator film of nmthickness.

Also, the single crystal fine particle of nm size is preferably anintrinsic or impurity-doped Si single crystal fine particle of nm size,and the insulator film is preferably a SiO₂ film of nm thickness.

Said fluorescent fine particle of nm size may be a semiconductor fineparticle having a band gap energy corresponding to an energy rangingfrom ultraviolet light to visible light. Also, a fluorescent fineparticle of nm size may have a donor or/and an acceptor. Still further,a fluorescent fine particle of nm size may be a semiconductor fineparticle involving luminous atoms or luminous atom ions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will better be understood from the followingdetailed description and the drawings attached hereto showing certainillustrative forms of embodiment of the present invention; in thisconnection, it should be noted that such forms of embodiment illustratedin the accompanying drawings hereof are intended in no way to limit thepresent invention but to facilitate an explanation and an understandingthereof, in which drawings:

FIG. 1 is a diagrammatic cross-sectional view showing the makeup of asolid state light-emissive display apparatus of the present invention,wherein (a) is a drawing showing the makeup of double layer laminationof a layer composed of crystal fine particles coated with insulator anda layer composed of fluorescent fine particles, (b) is a drawing showingthe makeup of alternate lamination of each one layer composed of crystalfine particles coated with insulator and composed of fluorescent fineparticles, and (c) is a drawing showing the makeup of lamination of amixed layer composed of crystal fine particles coated with insulator andfluorescent fine particles;

FIG. 2 is a diagrammatic drawing for explanation of operating principleof a solid state light-emissive display apparatus of the presentinvention, wherein (a) shows an enlarged view of crystal fine particlescoated with insulator, and (b) shows an enlarged view of fluorescentfine particles;

FIG. 3 shows the makeup of a solid state light-emissive displayapparatus of the present invention by simple matrix driving, wherein (a)is a cross-sectional view, and (b) is a plan view;

FIG. 4 shows the makeup of a solid state light-emissive displayapparatus of the present invention by active driving, wherein (a) is across-sectional view, and (b) is a plan view;

FIG. 5 is a drawing for explanation of the method of manufacture ofSiO₂-coated Si single crystal fine particles in accordance with thepresent invention; and

FIG. 6 is a drawing for explanation of the method of lamination ofcrystal fine particles coated with insulator and fluorescent fineparticles in accordance with the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, a detailed explanation is given in respect to embodiment ofthe present invention, references being made to figures. In the drawingfigures, it should be noted that the same reference characters are usedto designate substantially the same or corresponding components.

FIG. 1 is a diagrammatic cross-sectional view showing the makeup of aluminous part of a solid state light-emissive display apparatus of thepresent invention. FIG. 1( a) is a drawing showing the makeup of doublelayer lamination of a layer composed of crystal fine particles coatedwith insulator layer and a layer composed of fluorescent fine particleslayer, FIG. 1( b) is a drawing showing the makeup of alternatelamination of each one layer composed of crystal fine particles coatedwith insulator layer and of fluorescent fine particles, and FIG. 1( c)is a drawing showing the makeup of lamination of a mixed layer composedof crystal fine particles coated with insulator layer and fluorescentfine particles.

In FIG. 1, a luminous part 1 consists of a lower electrode 2, a luminousthin film 3 laminated on the lower electrode 2, and a transparent upperelectrode 4 formed on the luminous thin film 3. Said luminous thin film3, in case of FIG. 1( a), consists of laminating a layer 6 composed ofcrystal fine particles coated with insulator and a layer 8 composed offluorescent fine particles 7. Also in case of FIG. 1( b), said luminousthin film 3 consists of alternately laminating of a layer 6 composed ofcrystal fine particles coated with insulator and a layer 8 composed offluorescent fine particles 7. Further in case of FIG. 1( c), saidluminous thin film 3 consists of laminating a mixed layer of crystalfine particles coated with insulators 5 and fluorescent fine particles7. Said lower electrode 2 is, for example, n-type high conductive Sisubstrate 2, and said upper electrode 4 is ITO film which is conductiveand transparent to visible light.

FIG. 2 is a diagrammatic drawing for explanation of operating principleof a solid state light-emissive display apparatus of the presentinvention, wherein, FIG. 2( a) shows an enlarged view of layers ofcrystal fine particles coated with insulator, and FIG. 2( b) shows anenlarged view of layers of fluorescent fine particles.

In FIG. 2( a), said layers 6 are constituted as that crystal fineparticles coated with insulator 5 are mutually and densely aligned, andthis figure shows for an example where crystal fine particle coated withinsulators 5 is Si single crystal fine particle of nm size 5 a coatedwith SiO₂ film of nm thickness 5 b. Typically in size, the diameter ofSi single crystal fine particle 5 a is 7 nm, and the thickness of theSiO₂ film is 3 nm.

In FIG. 2( b), said layers 8 are constituted as that fluorescent fineparticles 7 are mutually and densely aligned, and said fluorescent fineparticle 7 is the semiconductor, for example ZnS, having the band gapenergy corresponding to the energy ranging from ultraviolet light tovisible light.

An explanation is next made in respect to luminescence mechanism of saidluminous part.

Voltage is applied between the lower electrode 2 and the upper electrode4 so as to be positively high at the upper electrode 4. The voltage isdistributed to respective insulators 5 b of crystal fine particlescoated with insulators 5 constituting the layer 6, that is, SiO₂ film 5b of SiO₂ coated Si single crystal fine particles 5. The electrons 9withdrawn from the lower electrode 2 are accelerated by the electricfield distributed to SiO₂ films 5 b, and pass through SiO₂ films 5 b bytunneling or resonant tunneling transporting phenomenon, since thethickness of SiO₂ film 5 b is thin. Since the diameter of a Si singlecrystal fine particle 5 a is small, the electrons in Si single crystalfine particles 5 a pass without being scattered by phonons because ofquantum size effect, that is, without loss of kinetic energy. As shownin FIG. 2( a), electrons 9 repeat acceleration in SiO₂ film 5 b andlossless passing through Si single crystal fine particle 5 a at everySiO₂ coated Si single crystal fine particle 5, whereby to obtain akinetic energy sufficient to excite fluorescent fine particles 7 and toemit from layers 6 composed of SiO₂ coated Si single crystal fineparticles.

As shown in FIG. 2( b), the electrons 9 which have obtained the kineticenergy sufficient to excite fluorescent fine particles 7, collide withfluorescent fine particles of nm size 7, and by the collision excitationcreate free electrons 11 and holes 12 in the conduction band and thevalence band of fluorescent fine particles 7. Said electrons 11 and saidholes 12 form free excitons 13 by coulomb potential based on therespective electric charges. Since these electrons 11 and holes 12 areenclosed inside the fluorescent fine particle of nm size 7, that is, inthe space of nm size, their coulomb interaction is strong, and theformation probability of free exciton 13 increases, whereby the freeexciton concentration increases. Since the free exciton concentration ishigh, luminescence intensity generated by extinction of free excitons 13increases. Since the free exciton energy depends on the band gap energyof the semiconductor crystal, luminescence wavelength can be chosen bychoosing the kind of semiconductor. For example, blue color luminescencecan be obtained by using ZnS semiconductor, and red color luminescencecan be obtained by using GaAs semiconductor.

Thus, in accordance with the present invention, the generationefficiency of high energy electrons to excite fluorescent fine particlesis quite high, and the exciton concentration is also quite high,therefore, high efficiency and high brightness luminescence can beobtained.

Also, since electrons 9 are not scattered by phonons in the process ofacceleration, dielectric breakdown of crystal fine particle coated withinsulators 5 does not tend to occur. Consequently, since it is possibleto make the thickness of fluorescent thin film 3 extremely thin to raisethe electric field intensity, a solid state light-emissive displayapparatus which is extremely thin type and has high reliability can beobtained.

Also in case that a fluorescent fine particle 7 is doped with a donor oran acceptor, an exciton formed via a donor or an acceptor, namely abound exciton 13 is formed. In case that a donor and an acceptor aredoped, a bound exciton 13 is formed via a donor and an acceptor. In thiscase, too, since electrons 11 and holes 12 are enclosed insidefluorescent fine particles 7, that is, in the space of nm size, theircoulomb interaction is very strong, and the formation probability ofbound excitons 13 increases, whereby the bound exciton concentrationincreases. Since the bound exciton concentration is high in this way,luminescence intensity generated by extinction of bound excitons 13increases. Also in this case, the luminescence wavelength correspondingto the depth of energy levels of a donor and an acceptor can beobtained. For example, ZnS doped with Al as a donor and Cu as anacceptor provides green light luminescence. Also, by using asemiconductor including luminous atoms or luminous atom ions forfluorescent fine particles 7, the accelerated electrons 9 excite theluminous atoms or luminous atom ions by collision excitation, whereby togenerate fluorescence of specific wavelength when the luminous atoms orthe luminous atom ions transit from the excited state to the groundstate. For example, if Mn is included as luminous atoms in ZnSsemiconductor, yellowish orange luminescence can be obtained.

According to the present invention, since electrons 9 can be acceleratedat quite high efficiency, fluorescent fine particle layers 8 havingluminous center atoms can be made to emit light of high brightness.

As described above, according to the present invention, electrons can beaccelerated at quite high efficiency. Theoretically mentioned, sinceelectrons can be accelerated without energy loss, it is possible toobtain luminescence with an applied voltage corresponding to the bandgap energy of fluorescent fine particles. For example, if ZnSsemiconductor is used as semiconductor of fluorescent fine particles,luminescence is obtained with the applied voltage of about 4V, becausethe band gap energy of ZnS is about 3.7 eV. Consequently, luminescenceof high brightness is possible also by the makeup of FIGS. 1( b) and(c).

An explanation is next given in respect to a solid state light-emissivedisplay apparatus of the present invention by simple matrix driving.

FIG. 3 shows the makeup of a solid state light-emissive displayapparatus of the present invention by simple matrix driving, whereinFIG. 3( a) is a cross-sectional view, and FIG. 3( b) is a plan view. Asolid state light-emissive display apparatus 30 comprises a substrate31, a plurality of the lower electrodes 2 in a form of mutually parallelstripes formed on said substrate 31, luminous thin film 3 laminated onsaid substrate 31 with the lower electrode 2 formed on the same, a theplurality of the upper electrodes 4 in a form of mutually parallelstripes formed on said luminous thin film 3 so to form a perpendicularmatrix with said lower electrode 2. Said upper electrode 4 is made oftransparent ITO film.

By making the cross-sectional regions of the lower electrode 2 and theupper electrode 4 as pixels, choosing an arbitrary one set from theplurality of the lower electrodes 2 and the plurality of the upperelectrodes 4, and by applying a voltage between the lower electrodes 2and the upper electrodes 4, the pixels at arbitrary positions are madeluminous.

In accordance with the above mentioned, images and mobile images can bedisplayed. Since the luminous thin film explained in FIG. 1 and FIG. 2is used, a solid state light-emissive display apparatus 30 of highefficiency and high brightness luminescence, thin type, and highreliability is provided.

An explanation is next given in respect to a solid state light-emissivedisplay apparatus of the present invention by active driving.

FIG. 4 shows the makeup of a solid state light-emissive displayapparatus of the present invention by active driving, wherein FIG. 4( a)is a cross-sectional view, and FIG. 4( b) is a plan view. A solid statelight-emissive display apparatus 40 of the present invention comprises aplurality of the scanning wirings 41 in a form of mutually parallelstripes formed on a substrate 31, the first insulation layer 42laminated on the substrate 31 having said scanning wirings 41 formed onthe substrate, a plurality of the signal wirings 43 in a form ofmutually parallel stripes formed on said first insulation layer 42 so toform a perpendicular matrix with said scanning wiring 41, the secondinsulation layer 44 laminated on said first insulation layer 42 havingsaid signal wirings 43 formed on the first insulation layer 42, thepixel electrodes 45 formed on said second insulation layer 44 and in theproximity of matrix cross sectional region, the luminous thin film 3laminated on said second insulation layer 44 having pixel electrodes 45formed on the second insulation layer 44, and the transparent upperelectrode 4 covering the whole display surface formed on said luminousthin film 3.

Near matrix cross sectional region and on said scanning wiring 41 is seta gate electrode 46 of a thin film transistor protruding into the firstinsulation layer 42, a channel semiconductor layer 47 of a thin filmtransistor is set opposing to said gate electrode 46 on the firstinsulation layer 42, one end of said channel 47 is connected to thesignal wiring 43 via a drain electrode 48, and the other end of saidchannel 47 is connected to the pixel electrode 45 via a source electrode49.

In accordance with the above mentioned, images and mobile images can bedisplayed. As a luminous thin film explained in FIGS. 1 and 2 is used inthe present invention, a solid state light-emissive display apparatus ofhighly efficient and bright luminescence, thin type, and of highreliability can be provided. Also according to the present makeup, sincethe voltage ratio between a pixel electrode switched on by a thin filmtransistor and a pixel electrode switched off by a thin film transistoris large, the extinction ratio between pixels becomes high, and so highresolution display is made possible. High speed display is also possiblebecause it can be driven with smaller power than by simple matrixsystem.

Explanation is next given in respect to the method of manufacture of asolid state light-emissive display apparatus of the present invention.

The method of manufacture is first explained in respect to the making ofthe single crystal fine particles coated with insulator consisting of Sisingle crystal fine particles coated with SiO₂ film.

FIG. 5 is a drawing for explanation of the method of manufacturing ofSiO₂-coated Si single crystal fine particles in accordance with thepresent invention. In this figure, the manufacturing apparatus 50 hasopen tube which consists of a part 51 for producing Si single crystalfine particles and a part 52 for coating single crystal fine particleswith SiO₂ film, wherein SiH₄ (silane) gas 54 is made to flow into thetube from the inlet 53, SiH₄ gas 54 is pyrolized to form said Si singlecrystal fine particles 5 a of nm size at the part 51 which is held atthe pyrolysis temperature of SiH₄ 54, and Si single crystal fineparticles produced are floating in the atmosphere. Si single crystalfine particles 5 a thus produced are transferred into said part 52 bythe gas flow, that is, by flowing gas, or by gravity, and SiO₂ film 5 bof nm thickness is formed on the surface of Si single crystal fineparticles 5 a in the state of floating in the atmosphere by oxygen 55introduced into a part 52. The SiO₂-coated Si single crystal fineparticles 5 thus formed are transferred to the outlet 56 by flowing gasor by gravity and collected.

By the method mentioned above, it is possible to produce SiO₂-coated Sisingle crystal fine particles mutually separated without forming porousaggregate formed by mutual contact of said single crystal fineparticles.

Explanation is next made in respect to the formation of luminous thinfilm by laminating of single crystal fine particles coated withinsulator and fluorescent fine particles on a substrate.

FIG. 6 is a drawing for explanation of the method of laminating ofsingle crystal fine particles coated with insulator and fluorescent fineparticles in accordance with the present invention.

The figure shows soaking the substrate 62 into the solvent 61 such aswater and pulling up said substrate, wherein said substrate 62 has thelower electrodes 2 or the pixel electrodes 45 formed on it and in saidsolvent 61 single crystal fine particles coated with insulator 5 orfluorescent fine particles 7 are dissolved. The fine particles 63 whichare single crystal fine particles coated with insulator 5 or fluorescentfine particles 7 in the solvent 61 are adhered to the substrate surface62 so as to minimize the surface free energies such as the surfacetension energy of the solvent 61, and the adsorption energy of fineparticles 63 to the substrate 62, as the result, a mono layer 64consisting of the fine particles 63 aligned mutually and densely on thesubstrate 62 is formed.

By the repeating of soaking and pulling up of the substrate 62, the fineparticle layers 64 can be mutually and densely laminated to desiredthickness corresponding to the repeating number.

In order to form the luminous thin film 3 of the makeup shown in FIG. 1(a), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved individually in differentsolvents, and the above mentioned repeating process is repeated with onesolvent to laminate to the desired thickness, followed by the repeatingprocess with the other solvent to laminate to the desired thickness.

In order to form the luminous thin film 3 of the makeup shown in FIG. 1(b), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved individually in differentsolvents, and the above mentioned repeating process is alternatelyrepeated with each solvent to laminate the layer 6 of single crystalfine particles coated with insulator and the layer 8 of fluorescent fineparticles alternately one by one.

In order to form the luminous thin film 3 of the makeup shown in FIG. 1(c), single crystal fine particles coated with insulator 5 andfluorescent fine particles 7 are dissolved in a common solvent, theabove mentioned repeating process is repeated with the common solvent tolaminate the mixed layer of crystal fine particles coated with insulator5 and fluorescent fine particles 7 to the desired thickness.

Since fine particles are aligned densely with few gaps in the luminousthin film thus formed, the electric field distribution is uniform,tunneling probability increases, and electrons can be accelerated athigh efficiency. Also, brightness is high because fluorescent fineparticles are densely aligned.

INDUSTRIAL APPLICABILITY

As will have been appreciated from the foregoing description, thepresent invention provides a solid state light-emissive displayapparatus of dramatically higher brightness and efficiency, higherreliability, and of thinner type than existing display apparatuses. Alsoin accordance with the present invention, this solid statelight-emissive display apparatus can be manufactured at low cost. Thus,if the apparatus of the present invention is used as the displayapparatus of mobile phones or others, it is quite useful because of muchlower power consumption, higher brightness, thinner type, and higherreliability than existing liquid crystal displays.

1. A solid state light-emissive display apparatus, characterized in thatit comprises: a luminous part comprising a luminous thin film composedof laminated or mixed of crystal fine particles coated with insulator ofnm (nanometer) size and fluorescent fine particles of nm size; and alower electrode and a transparent upper electrode sandwiching saidluminous thin film, whereby to obtain luminous display by impressingalternating voltage or direct current voltage between said upper andlower electrodes.
 2. A solid state light-emissive display apparatus asset forth in claim 1, characterized in that: said crystal fine particlescoated with insulator of nm size consist of single crystal fine particleof nm size of either a semiconductor or a metal, and an insulator filmof nm thickness coating the surface of said single crystal fineparticle.
 3. A solid state light-emissive display apparatus as set forthin claim 2, characterized in that: said single crystal fine particles ofnm size are either intrinsic Si single crystal fine particles of nm sizeor those doped with impurities, and said insulator film is SiO₂ film ofnm thickness coating the surface of said Si single crystal fineparticles.
 4. A solid state light-emissive display apparatus as setforth in claim 1, characterized in that: said fluorescent fine particlesof nm size are the semiconductor fine particles having a band gap energycorresponding to an energy ranging from ultraviolet light to visiblelight.
 5. A solid state light-emissive display apparatus as set forth inclaim 4, characterized in that: said fluorescent fine particles of nmsize have either a donor or/and an acceptor.
 6. A solid statelight-emissive display apparatus as set forth in claim 4 or 5,characterized in that: said fluorescent fine particles of nm size arethe semiconductor fine particles involved with either a luminous atomsor a luminous atom ions.
 7. A solid state light-emissive displayapparatus as set forth in claim 1, characterized in that: said upper andlower electrodes are formed in a form of matrix configuration, andintersection regions of said upper and lower electrodes are used aspixels which are driven by simple matrix driven operation.
 8. A solidstate light-emissive display apparatus as set forth in claim 1,characterized in that: scanning wirings and signal wirings are formed ina form of matrix, a thin film transistor is set at an intersectionregion of said scanning wiring and said signal wiring, a gate electrodeof said thin film transistor is connected to said scanning wiring, adrain electrode of said thin film transistor is connected to said signalwiring, a source electrode of said thin film transistor is connected toa pixel electrode, said luminous thin film is sandwiched by said pixelelectrode and said upper electrode, whereby each said pixel is activelydriven by said thin film transistors by choosing said scanning wiringand signal wiring.
 9. A method of manufacturing of a solid statelight-emissive apparatus, characterized in that it comprises steps:producing Si single crystal fine particles of nm size by pyrolyzing SiH₄in a floating state of said Si single crystal fine particles inatmosphere; transferring said Si single crystal fine particles in thestate of floating into O₂ gas atmosphere; and coating the surface ofsaid Si single crystal fine particles with SiO₂ film of nm thickness.10. A method of manufacturing of a solid state light-emissive apparatus,characterized in that it comprises steps: dissolving crystal fineparticles coated with insulator of nm size and fluorescent fineparticles of nm size into respective solvents; and soaking a substrateinto each solvent and pulling it up, whereby laminating of a singlecrystal fine particle layer and a fluorescent fine particle layer.
 11. Amethod of manufacturing of a solid state light-emissive apparatus,characterized in that it comprises steps: dissolving crystal fineparticle coated with insulator of nm size and fluorescent fine particlesof nm size into common solvent; and soaking a substrate into saidsolvent and pulling it up, whereby laminating a mixed layer composed ofsingle crystal fine particles coated with insulator and fluorescent fineparticles.
 12. A method of manufacturing of a solid state light-emissiveapparatus as set forth in claim 10 or 11, characterized in that: saidcrystal fine particle coated with insulator of nm size consists of asingle crystal fine particle of nm size of either a semiconductor or ametal, and an insulator film of nm thickness coating the surface of saidsingle crystal fine particle.
 13. A method of manufacturing of a solidstate light-emissive apparatus as set forth in claim 12, characterizedin that: said single crystal fine particle of nm size is eitherintrinsic Si single crystal fine particle of nm size or that doped withimpurity, and said insulator film is SiO₂ film of nm thickness coatingthe surface of said Si single crystal fine particle.
 14. A method ofmanufacturing of a solid state light-emissive apparatus as set forth inclaim 10 or 11, characterized in that: said fluorescent fine particle ofnm size is a semiconductor fine particle having a band gap energycorresponding to an energy ranging from ultraviolet light to visiblelight.
 15. A method of manufacturing of a solid state light-emissiveapparatus as set forth in claim 10 or 11, characterized in that: saidfluorescent fine particle of nm size has a donor or/and an acceptor. 16.A method of manufacturing of a solid state light-emissive apparatus asset forth in claim 14, characterized in that: said fluorescent fineparticle of nm size is a semiconductor fine particle involving aluminous atoms or a luminous atom ions.